How to properly connect a water heat exchanger. Do-it-yourself heat exchangers for furnaces with a water circuit. Video: Chimney in a water jacket

- the heart of the heating system, designed to transfer heat through the media and heat the room. The medium in the system can be liquid, vapor - gaseous. simple device a room radiator with a water source of heat is considered.

The degree of heat conductivity depends on the intermediate material in the system, that is, the heat exchanger, the best conductivity indicators for silver and copper. Copper is used, of course, more often. Its heat transfer is almost 8 times higher than, for example, steel, plastic is many times worse.

Principle of operation

Not a single boiler heating system can do without a copper heat exchanger. The principle of operation is simple. Water begins to circulate through the coils in the pipes, heats up, flows into the pipeline of the system, into the radiators, from which it returns back, already cooled down.

In private houses, a heat exchanger is installed in order to turn the stove into a water heating boiler. At homemade device it is important to consider the size and shape so that the exchanger is combined with the dimensions of the stove chamber.

Radiators, a pipeline are connected to the exchanger, pipes heat up evenly, heat is distributed throughout the house.

Advantages and disadvantages

The clear advantages of the heat exchanger include:

ease of manufacture and installation;
heating can be combined, in addition to heating, install a water heating system;
fuel for the device can be varied: solid, gas - liquid;
appliances are beautiful in appearance, you can give the interior a national style.

The disadvantages of the heat exchanger are two:

there is no automatic control over the heating of the carrier;
The efficiency is not too high.

Heat exchanger using tube board

Types of heat exchangers

Heat exchangers, depending on their purpose, are cooling and heating:

The cooling device is in contact with a liquid or cold gas, while cooling the hot one.
A heating device with a heated gas or liquid gives off heat to the circulating flows of a cold liquid, gas, and an exchange takes place.

Structurally, heat exchangers are:

surface, at contacts of media through an intermediate surface;
regenerative, when fed to the nozzle either cold or hot water due to heating and cooling, the temperature regime is regulated and maintained;
mixing, the supply of media from one to another by mixing them.

Surface heat exchangers may have different shape, are:

lamellar, consisting of many plates with fluid passing through their labyrinths;
in the form of coils, thin tubes twisted into a spiral;
a pipe in a pipe, consisting of two tubes of different diameters and placed one inside the other.

How to make an exchanger with your own hands

For a heat exchanger with a tank, you will need a tank, a pair of copper tubes. You can use sheet steel with a thickness of 2.5-3 mm, weld a tank of the required volume from it.
Install the container from the floor at least 1 meter, from the oven - at least 3 meters.
Make two holes on the right, closer to the structure and on the left - at the top.
Bring the lower outlet to the furnace, at an inclination of 2-3 degrees.
Connect the top outlet at an angle of 20 degrees, only in the opposite direction.
Insert a tap into the bottom outlet at the outlet to drain the water from the tank.
Below is another faucet to drain water from the entire system.
Check the design, it must be airtight, you can fill it with water and, under light pressure, identify leaks and eliminate them.

Required materials, tools drawings

For the heat exchanger it is worth choosing:

Capacity for 90 -110 liters.
Anode.
Copper tube up to 400 cm long for the thermal heater. If there is no copper pipe, you can use aluminum, metal-plastic, if only it bends well.
Power regulator to control the heat supply.

It is not necessary to make a coil of steel, the material is bad for heat dissipation, it does not bend, the air heats up many times faster thanks to copper. When using steel, a pipe bender is additionally required.

Walkthrough

Production of a channelless heat exchanger

Prepare a container, metal is better, plastic will take longer to heat up.
Install the tank to the top of the heating system.
Make 2 holes in the container for exits. One is at the top through which hot water will be discharged. The second is at the bottom, cold liquid will come from the pipes of the system.
Place the outlets correctly, the rate of heat transfer will depend on this.
Seal the holes tightly so that the air temperature is not wasted on the battery, and the room warms up evenly.
Use copper for the tube, it should bend well and give off maximum heat to the room.
Bend the tube in the form of a spiral, you get a coil.
Place the spiral in the tank, the ends of the tube must be brought out, well fixed.
Connect a threaded fitting to the ends of the parts.
Connect a power regulator to the pipe, you can buy it in a store, it is inexpensive, so you should not get hung up on self-production.
The system will work properly even without a regulator, but it is needed to regulate power and save electricity. Power can be set to your liking.
Connect the terminals to the thermostat, then the power wires.
To prevent the tank from wearing out from temperature changes, install an anode.
Seal all elements tightly.
Fill the tank with water, the heat exchanger is ready.

Production of different types of heat exchanger

Water

The device has two sectors that heat each other. The circulation of water at high power occurs in a closed circuit in the reservoir of the heating system, where it heats up to 180 gr. After flowing around the installed pipes, the water is sent to the main system, where the heating temperature increases.

To make a water heat exchanger, prepare:

Container in the form of a steel tank. Set it to the beginning of the system. For water circulation, 2 branches from pipes are needed, the lower one is for entry cold water, top - for hot entry.
Check tank for leaks.
Place copper tubular coils inside the tank, 4 meters of pipe per 100 liters of tank is enough.
Connect the power regulator to the copper tube.
To prevent pressure and temperature drops from destroying the container, install the anode closer to the heating element.
Seal the tank tightly.
Fill with water.
Check the system in action.

lamellar

One-piece construction block consists of alternately placed plates with hot and cold media. Mixing of media does not occur, since the seal is rubber and multi-layered. Plate species are difficult to handmade, the tightness of the internal plates is important, and this requires special equipment.

Pipe in a pipe

The exchange is made up of big pipe and smaller in diameter, inserted inside. The media move along the smaller pipe and are fed into the outer pipe for cooling. Design:

easy to manufacture;
easy to clean;
durable;
applicable to any coolant;
unlike lamellar pipe, it can work under pressure;
by changing the dimensions of the pipes, you can choose the optimal speed for the movement of fluid.

To prevent pipes from costing you a pretty penny, carefully calculate the material consumption.

To make a structure, select two copper tubes in diameter, one larger than the other by 4 mm for a gap:

Side weld the tee to both sides of the outer pipe.
Insert the smaller tube, weld the ends of the large tube, fix the position of the smaller tube.
weld short tubes to the outlet tees, liquid will move through them.
When using steel material, increase the surface area, assemble the battery from the exchangers separately.
Connect the tubes in segments, weld alternately to both tees to make a snake.

Air

The air heat exchanger consists of a radiator and a fan. The fan cools the air flows, disperses them throughout the ventilation system. These types of exchangers are installed in administration buildings for public purposes.

DIY heat exchanger

How to make a booster for flushing a heat exchanger

The booster consists of a tank, a water circulation pump and an electric heating element. It is not necessary to disassemble the heating boiler for flushing, it is enough to disconnect the nozzles, connect a hose to one of them with the injection of a chemical solution through it into the unit. The solution will pour out through another pipe, but a hose must also be connected to it.

Of the chemical reagents, hydrochloric, sulfuric acid is mainly used, phosphoric, nitric acid can be poured.

It is not difficult to flush the heat exchanger, but it is necessary to observe safety precautions, that is, first disconnect the device from the power source, be it gas, water, electricity. Dismantling must be done carefully, a damaged seal can lead to leakage of the structure, the equipment will quickly fail.

The heat exchanger is important to design correctly, calculate economic efficiency, percentage of hydraulics, designate heat losses, calculate the design according to the geometric parameters of the unit and its components, calculate the thermal insulation of the device.
Choose a DIY design in a simpler way, it is almost impossible to make a factory unit.
You can connect the heat exchanger to the system using fittings, put one at the bottom for cold water inlet, the second at the top for hot water inlet.
When installing the exchanger install the pipes at a slope according to the diagram.
When installing the unit to the oven and the use of coal as a material for the exchanger, it is better to choose cast iron, it is durable, fireproof.
To make a do-it-yourself exchanger take any model as an example and follow its parameters.
When using the oven for heating purposes and water supply, the exchanger should take on itself no more than a tenth of the generated heat.
Pellets- good fuel and cheap in price, soot is not emitted, it is very important for cleanliness.
Check the seams at the exchanger, they must not be allowed to leak, under pressure or high temperatures the entire structure may become unusable.
Make the right calculations otherwise the work will cost you dearly.
The tube-in-tube heat exchanger is easy to clean, serves for a long time, is simply manufactured, can work under pressure. It is considered the most acceptable option for hand-made production.

As you can see, making a heat exchanger yourself is not difficult. For a simple design, a tank, two copper pipes of different diameters, a coil and a fan are enough. Due to the device, you can not only heat the room, but also cool it.

A thing, like an exchanger in one form or another, is available in almost every home. Approach the work constructively and thoroughly, make drawings, decide on the choice of material, follow the instructions for manufacturing, assembling and connecting the device described above.

If you wish and consistent actions, you will assemble the structure no worse than the store, the house will be warm and comfortable, and the device will work flawlessly for a long time.

For heating residential buildings, there is a wide range of heat generators that differ in design and types of fuel. If the building is located far from large settlements or is used periodically, the best option will install the system furnace heating.

The stove heat exchanger used in this design will ensure uniform heating of the entire house, as well as provide required amount hot water.

Application specifics

Standard stove heating implies an uneven distribution of thermal energy - the farther from the source, the colder. After connecting the radiators and pouring water, the furnaces act as analogues of solid fuel boilers, providing heating of the coolant, smoke channels and walls. Such a system during the furnace will allow heat to be transferred from the coil to the radiators, and after the fuel is extinguished, it will use the energy of the heated walls of the furnace.

When installing a heat exchanger, it should be taken into account that its installation will reduce the useful volume of the fuel compartment and fuel will have to be added much more often. The correct design of the water circuit and its relationship with the dimensions of the heating chamber will help eliminate this problem. A good alternative would be a long-burning stove.

There are some nuances in such an upgrade of the heating system. The energy that is released during the combustion of firewood will begin to heat the heat exchange unit and the working fluid placed in it, but the furnace walls will not change their temperature.

The upper part of the body with smoke channels will be heated. If the building is used as a temporary residence, the oven will not turn on regularly and may cause the liquid inside the pipes to freeze. In order to prevent accidents, it is recommended to replace water with antifreeze.

Advantages

Installing a water circuit in the furnace heating system allows you to increase the efficiency of fuel consumption.

The energy of the burnt coolant is spent on heating the body, smoke channels and walls, and also provides a high temperature for the water circulating through the pipes.

For property owners, this method provides additional benefits:

ease of manufacture (brick ovens are often installed in residential buildings, and for high-quality energy distribution it is enough to make a home-made heat exchanger by connecting it to the heating system of the building);
combined heating due to warm air from the furnace and hot water from batteries;
a variety of fuel types (most boilers for heating use only one type of energy carrier, which can be expensive and inefficient, and a brick oven heat exchanger works with any solid fuel);
nice appearance(design country house often takes place in the national style, but the installation of heat exchange units does not violate the traditional look of the Russian stove).

Design features

If the owner of the building has experience in laying bricks or kiln works, installation can be done by hand. Before connecting the water heating system, you will also need to make a heat exchange unit.

Despite the fact that the construction market offers a large selection of prefabricated structures, independent production more profitable. A self-made installation allows you to take into account all the parameters of this particular furnace, its placement and dimensions of the fuel compartment.

Pipe heat exchanger

The device of a furnace heating system with a water circuit involves the installation of a heat exchanger in the fuel compartment of the furnace and the connection of pipes to it for supplying the working fluid. For heating and cooking stoves and stoves, coils welded from pipes and placed in metal containers are well suited. Their manufacture requires professionalism, and cleaning from combustion products is quite laborious, but the sinuous surface will provide fast heating.

The 50 mm U-shaped pipes used in the construction can be replaced with segments profile pipes 40x60 mm. This will simplify welding work and greatly facilitate installation. If the oven is not used for cooking, additional small diameter tubes are welded to the top of the heat exchanger. A do-it-yourself design will give off much more heat.

Devices of this type are used in ovens designed exclusively for space heating. For their manufacture, you will need sheet metal half a centimeter thick, sections of rectangular pipes 40x60 mm, as well as round tubes of the same diameter for supplying water to the working surface. The dimensions of the heat exchangers depend on the dimensions of the furnace compartments for fuel.

A similar heating system can be used for a heating and cooking stove or a simple stove. To do this, the structure must be mounted so that the heated gases from the fuel chamber move towards the upper shelf of the register, flow around it and enter the smoke channels.

An alternative option would be to manufacture a heat exchanger without a top shelf, the sides of which will be connected to round or rectangular pipes.

Installation of a heating device

Heat exchangers for brick ovens can be made by hand from metal 2.5 mm thick. The basis of the design will be two containers - a cylindrical upper and a rectangular lower one, interconnected by pipes. The conjugation of the seams should occur with a minimum gap, and the diameter of the pipes should be calculated based on the dimensions of the furnace and the area of \u200b\u200bthe heated room. After checking the accuracy of the calculations and re-measuring the workpieces, the parts are connected by welding.

The strength of the finished structure is determined after welding the bottom pipe, pouring water and connecting the outlets to the radiator tanks. When the installation is completed, it is necessary to fill the system with compressed air, controlling the pressure with a pressure gauge. Well-sealed seams will not leak. In case of detection of leaks or other defects, the water is drained and the problem areas are sealed. An important parameter during installation will be the total length of the pipes - the smaller it is, the better the space will be heated.

Nuances of installation and operation

During the installation of thermal units and their commissioning, it is necessary to follow the installation technology and avoid emergency situations. The high temperature in the heating chamber makes high demands on the quality of the metal, the rationality of the heat exchange unit and the quality of welding. knowledge of several simple rules will help ensure long-term and reliable operation of the furnace heating system.

The load-bearing contours of the heat exchangers must not be fixed to the walls with fixed connections. The temperature to which the pipes are heated causes the metal to expand, which can lead to a change in their dimensions.

Copper will be a good material for furnace heating pipes. The use of this metal will provide high thermal conductivity of the structure and ease of manufacture of the coil due to plasticity.

The cross section of the pipelines must be at least an inch. At smaller values, the circuit will become inertial, and the fluid flow in it will seriously slow down. The growth of heat losses in the heating mains will lead to a decrease in the efficiency - the room will become colder with the same fuel consumption.

Heat exchangers are common name devices united by the principle of operation.

They are used in chemical, oil, gas and other industries.

In everyday life they are used to increase efficiency homemade stoves, in boilers indirect heating, for the joint operation of different heat carriers, when one of them is more expensive (to save money), in general, wherever it is necessary to cool, heat or transfer the temperature of a liquid or gas.

How it works, why and how you can make a heat exchanger with your own hands.

So, the purpose of the device is to transfer temperature from one medium to another. Heat sources and coolants can be various liquids, gases and steam. Unstable media are separated by a material that has a suitable thermal conductivity for this. The simplest example of a heat exchanger is an ordinary room radiator. The source of heat is water in heating. The heated medium is the air in the room. And the separating material is the metal from which the radiator is made.

A large role in which intermediate material to use has its degree of thermal conductivity. The leaders in this indicator are silver and copper. But for obvious reasons, copper is most often used.

Heat exchanger device

Copper is 7.5 times better at transferring heat than steel, and plastic is 200 times worse than steel. It turns out that, other things being equal, 1.7 meters of copper, 12 meters of steel and 2000 meters plastic pipe transfer the same amount of heat.

Kinds

By appointment, heat exchangers are divided into:

Cooling.
Heating.

Heaters, on the contrary, contain a heated gas (liquid), which shares heat with a circulating cold liquid (gas).

Surface heat exchanger device

Both "heaters" and "coolers" can differ in design:

Surface (the case when the media are in contact through an intermediate surface).
Regenerative (alternating supply of cold and hot media to a special nozzle, which, heating and cooling, regulates the temperature of the media).
Mixing (feeding one medium directly into another and mixing them).

It must be said that surface heat exchangers are used most often. They differ significantly in form. Three types can be distinguished here:

Lamellar (many plates collected in cassettes, through the labyrinths of which liquid passes).
Coils (a thin tube twisted into a spiral).
Pipe in a pipe.

Dual fuel heating can be very convenient, especially when one of the heating sources fails. have two combustion chambers and are produced in different versions: gas - electricity, gas - coal, and so on. The design of the system and installation methods will be discussed below.

Consider the features of choosing a thermostat for a heating radiator.

The usual methods of heating in some situations may be inconvenient. Heating without gas and wood can be a good alternative..html consider ways to organize space heating without the use of wood and gas.

Making a "pipe in pipe" heat exchanger with your own hands

Principle of operation, pros and cons

As the name implies, the heat exchanger is a large pipe, inside of which a smaller one is located. The cooling or heating medium moves through the inner pipe, and the liquid to be cooled is supplied to the outer one.

A heat exchanger from a pipe can consist of several links connected in series.

This simple design has the following advantages:

suitable for any heat carriers;
easy to make yourself;
easy to clean;
serves for a long time;
suitable for work under pressure (unlike lamellar);
You can choose the speed of movement of liquids by changing the size of the pipes.

However, everything must be carefully calculated, and pipes can be quite expensive.

Manufacturing

You will need:

Tubes of different diameters (preferably copper) - 2 pcs.
T-tees (diameter is the same as that of the larger tube) - 2 pcs.
Short tubes of the same length, diameter = tee outlet. - 2 pcs.
Welding and electrodes, or a powerful soldering iron and solder for copper.
Bulgarian.
Roulette.

We will use thin-walled copper tubes. We select segments that are suitable in length so that the diameter of one is at least 4 mm larger than the other (the gap will be 2 mm on each side).

We weld tees on the outer tube on both sides (sideways).
We insert a tube of smaller diameter inside and, by welding the ends of the larger tube, we fix the inner tube in it.
We weld short tubes to the outlets of the T-shaped tees, through which the liquid will fit.
If not a copper, but a steel billet was used, its effectiveness will be significantly lower. It makes sense to increase the working surface area by making a battery of separate heat exchangers. They are connected in series by small sections of pipes, welded to one or the other tee. The result should be a snake.

To work with polluted media, heat exchangers are made collapsible so that it can be cleaned in the future. For clean liquids, non-separable heat exchangers are made.

Do-it-yourself air plate heat exchanger assembly with a fan

Let's make a household heater from a plate heat exchanger. It can, for example, be connected to a boiler with a water jacket.

You will need:

finished plate heat exchanger, small size;
branch pipes for air duct;
fan;
plywood for assembling the frame (its dimensions must match the dimensions of the side walls of the heat exchanger) - 4 pcs;
plywood for the front of the frame - 1 pc;
Metal sheet;
a bar (of such length that it is enough for a frame and 4 short bars);
self-tapping screws;
roulette;
jigsaw;
screwdriver.

Progress:

A box is knocked down from plywood pieces. Internal corners are fixed with the help of bars on self-tapping screws. The heat exchanger must fit snugly into the frame.
We attach a sheet of metal to one side of the frame, cut a hole in the middle into which the fan will be inserted.
We make a frame from a bar. We fix it on the opposite side of the frame.
Air outlets are attached to the frame.

By installing such a device on the path of cold air from the street, you can get fresh, but warm air. Heat loss due to ventilation of the premises will be reduced by 3 times.

Do-it-yourself water heat exchanger for a furnace

To increase the efficiency of a boiler with a water circuit. metal structure from pipes of large diameter will be built into the furnace and connected to the heating pipeline.

A few general recommendations:

The diameter of the pipes must not be less than 2.5 cm. Otherwise, the heat exchanger will slow down the movement of the liquid.
Approximate calculation of the heat exchanger area: 1m 2 per 3-5 kW of furnace power.
But if the stove not only heats the house, but also heats the water, the heat exchanger must “take away” more than 1/10 of the heat.

The design of the heat exchanger is two horizontal pipes, between which a battery of 6-9 pipes of the same diameter is welded.

The exit of the heat exchanger is made at the top, the entrance (through which the return will be supplied) is at the bottom.
The inlet and outlet pipes are threaded for connection to heating pipes.
Installation in the cavity of the furnace begins at the stage of laying the foundation of the furnace.
As the rows of the furnace are built, the tubular structure is constantly attached and its position is controlled (to the coolant outlet a little higher from the level).
When the oven is finished, the heat exchanger is connected to the heating. This is done with a clutch. A long thread is cut at one of the ends, a narrow nut is screwed on, then the coupling is screwed all the way. The threads on the second pipe are wrapped with FUM tape, tow, etc., then the coupling is twisted in the opposite direction. In order not to leak the joint on the first pipe, the thread is also wrapped with FUM tape and pressed with a nut.
The system with a heat exchanger is filled with water and a test fire is made.

The quality of the seams must be perfect, because the heat exchanger will have to work at high temperatures, there will be no access to it, and leaks will lead to the repair of the entire furnace!

A variant of the heat exchanger for the furnace can be a tank, inside which passes part of the hot chimney. Such a device is easier to maintain, dismantle if necessary, but it is somewhat more difficult to make.

What to do with the power regulator?

A small, inexpensive device will save a lot of money and help you set the temperature on the heat exchanger to your desired temperature.

To install it on the heat exchanger tube, you need to connect the thermostat with the terminals, and then the power wires.

You can avoid unnecessary work by purchasing a regulator with a built-in heating device. There will be no noticeable difference in price.

The heat exchanger can be a great addition to the oven, it will increase its efficiency. It can be installed on the ventilation openings and heat the air passing into the house, provide the house hot water, make a conventional oven give off more heat and much more.

Very relevant information in a crisis, when money is scarce and prices are high. I, too, am now hunching over with heating in the country, leaning towards warm floors. I would like to read something on this subject.

A good way, of course, and more economical, but you need to have male artisan hands)) Well, it’s easier for a woman to buy ready-made equipment. But the idea is good, informative article for crazy hands

In order to use the furnace for water heating at home, its design includes a furnace boiler or heat exchanger, with the help of which the thermal energy of combustion of solid fuel is transferred to the system coolant. They may be the most different designs. In this article, we will look at some of them, as well as how you can make a furnace boiler or a heat exchanger for a furnace with your own hands.

Heat Exchanger Efficiency for Furnace

In order to decide which heat exchanger for the furnace to choose and which design is more efficient, it is necessary, initially, to find out what affects its efficiency. We can distinguish the following main factors affecting its heat transfer ability:

its surface area, the larger it is, the more energy is transferred;
thermal conductivity of the material from which it is made;
temperature difference - the larger it is, the more energy is transferred.

Based on this, the following conclusions can be drawn:

The design of the furnace boiler or heat exchanger for the furnace must be such that the area of its contact with the medium with high temperature (flame or hot gases) is maximized. Based on this, it can be concluded that boiler structures of the same dimensions made of pipes will be more efficient than the same ones made of sheet metal. Although the frequency of the pipes and their diameter also matter here. In order not to guess, you just need to calculate the total surface area of \u200b\u200bthe heat exchanger that will be in contact with the hot medium - the larger it is, the better. Even a student can do it.
For the manufacture of heat exchangers, it is necessary to use materials with good heat transfer ability. But besides this, they must withstand the temperature and aggressiveness of the environment from which it will take heat (firebox or chimney). From available materials, it can be steel or cast iron. Although steel is most often used: in the form of pipes or sheet. This is explained both by the presence of a wide range of its profiles and thicknesses, and by the relative simplicity of working with it: it is easy to weld or bend it to obtain a structure of the chosen shape. On the other hand, cast iron is more resistant to aggressive environments, but it is a brittle material that does not tolerate shocks and sudden temperature changes, so only ready-made cast sections can be used to manufacture a heat exchanger. One example of such a heat exchanger can be its design, made from sections of a conventional cast iron radiator, discussed below.
To ensure reliable natural circulation of the coolant, the difference in the temperature of the coolant at its inlet and outlet is important, the larger it is, the better the circulation will be. Therefore, the inlet pipe supplying “cold” water (return) and the outlet pipe with heated water should be located at different levels: the first at the base, and the second at the top of the chamber where heat exchange takes place (firebox, chimney, furnace hood). When using a circulation pump and forced circulation, this may not be so important, but in this case, for furnace boilers, it is necessary to ensure maximum natural circulation. Since in heating devices using solid fuels, which include stoves, forced circulation is almost never used in its pure form, but only in conjunction with natural circulation, with the ability to switch from one mode to another in the event of a power outage (using a bypass). And even if there are conditions for normal circulation, it is easier for the circulation pump to create forced circulation.

Now consider several designs of furnace boilers or heat exchangers for a furnace with a water circuit, from different materials, of varying complexity, but which it is quite possible to make with your own hands, if you have some skills in working with metal and the ability to carry out welding work. In extreme cases, you can choose a compromise option: choose the most suitable design, prepare materials: sheet metal or pipes of the required size and thickness, and entrust welding work to an experienced welder.

Designs of heat exchangers for heating furnaces

A feature of the heat exchanger for a heating furnace located in the firebox is that its upper part is usually closed with a sheet metal shelf or pipes. Since the maximum temperature of the flame is in its upper part, thus, the most efficient heat intake and its transfer to the coolant is achieved. Its design and dimensions must be such as to ensure maximum efficiency of the water circuit, but at the same time not interfere with the loading and normal combustion of fuel.
Such furnace boilers can be made from sheet metal 4-5 mm thick, round pipes with a diameter of 32-57 mm, or pipes of rectangular section 30-40x50-60 mm. It is best if the pipes used for this are seamless. Otherwise, the seam lines must be placed to the side brickwork and pre-weld.

Depending on the shape of the overlap of the firebox, such heat exchangers can be flat at the top (when overlapping with flat cast-iron slabs) or arched (with an arched brick ceiling).

Below are possible options for a heating stove with a flat top of the firebox:

Fig.1 Heat exchanger for a heating furnace made of sheet steel 4-5 mm thick.

In addition, a variant with a combination of sheet iron and pipes is possible, as in the photo on the left. Here, the upper solid shelf is replaced by a row of round pipes. At the same time, both in the first version and in the second, the "return" and the supply pipe can be welded on the side (on one side or on different sides) or at the back, depending on the location of the furnace and the layout of the water heating pipes.

It is also possible that the side walls of such a heat exchanger will also be replaced by pipes of a round or rectangular profile, while they can be located both vertically and horizontally.

For a heating furnace with an arched ceiling of the firebox, this version of a boiler made of pipes is possible:

A register of this form can even be used for a water circuit device in a Russian stove. In this case, the curvature of the bend of the pipes must correspond to the arch of its cooking chamber.

Designs of boilers for heating and cooking furnaces

Heat exchangers for heating and cooking stoves or stoves are distinguished by the fact that their upper surface must be completely or partially open for flame access to the hob. The side surfaces of such furnace boilers can also be made of sheet steel (“book”) or pipes.

If the heat exchanger is located outside the firebox, its design for heating and heating pipes may be the same. Here, the type, design and size of the place where the heat exchange registers will be installed, that is, the smoke channels or in their absence (bell-type furnaces), the dimensions of the hood, are of greater importance.

For heating and cooking stoves or cookers, such structures made of sheet iron and pipes are possible (photo or Fig. 2 below).

A variant is also possible only from pipes of a round and rectangular profile (Fig. 3).

Rice. 3 Variant of the register from pipes: 1 - pipes of a rectangular profile 40x60x4 mm; 2 - round seamless pipes with an outer diameter of 40 or 50 mm and a wall thickness of 4-5 mm; 3 - round pipes with a diameter of 32 or 40 mm; 4 - a pipe supplying heated water to a water heating system with a diameter of 50 mm; 5 - "return" with a diameter of 50 mm; a B C D- dimensions that are calculated depending on the required power of the boiler (see below), and are also taken in accordance with the dimensions of the firebox and the furnace door.

Another option is also possible from round pipes for a heating and cooking stove or a stove, as in the photo on the left, in the form of two horizontal circuits connected by vertical pipes.

It is also possible to have such a variant of a heat exchanger (boiler, register) from round pipes for a heating and cooking stove or stove:

Installation location: possible options

Most often, furnace boilers are installed in the firebox of heating, heating and cooking stoves or stoves. If in the case of a stove there is practically no other option, then for stoves another location is possible and, according to some experts, more efficient - outside the firebox. Because with the traditional location of the heat exchanger in the firebox, the water circulating in it reduces the temperature in it and, thus, worsens the conditions for the combustion of the fuel, which leads to its incomplete combustion, an increase in the amount of soot and a decrease in the efficiency of the furnace.

And the maximum effect is obtained when the water in the heat exchanger circuit moves towards the heat flow, that is, its colder part must come into contact with furnace gases that have a lower temperature, and its more heated part with hotter ones. In addition, in this case, the amount of condensate on the surface of the heat exchanger is reduced, which reduces its corrosion. When placing a furnace boiler in a firebox, it is difficult to provide such conditions.

The solution may be to locate the heat exchanger in the chimney flue of the furnace or its vertical flues (depending on the design). Especially attractive looks, from this point of view, bell-shaped chimney. Hot gases are retained in it until the furnace cools down. Inside it, you can simply place a heat exchanger of large volume and area of contact with hot gases, welded from pipes, and its various designs are possible. Hot gases in the hood first rise up and then fall down to the exit to the chimney, along the way giving up their thermal energy to the furnace boiler. In the same way, it is possible to consider the placement of the register in vertical smoke circuits with the movement of flue gases down. But at the same time, it must be taken into account that their cross section must be sufficient to provide good traction.

Although in each case, the choice of location must be considered depending on the type of furnace, its design and shape, as well as the type and design of the heat exchanger itself used.

How to calculate the power and dimensions of a heat exchanger for a furnace

The power of the heat exchanger of the water circuit of the furnace, which is necessary for heating the premises of the house, depends on their area (volume) and the degree of insulation of the enclosing structures: the walls themselves, ceilings, windows and doors. As an average, you can focus on 1-1.2 kW for every 10 m 2 with a ceiling height of 2.5-2.7 m. That is, for a house with an area of 100 m 2, on average, you may need a furnace boiler with a thermal power of 10-12 kW.
The power of the heat exchanger itself depends on the surface area of contact with the hot medium (fire or hot gases). On average, it is considered that its specific thermal power is from 5 to 10 kW per 1 m 2 of the contact area of such a boiler, depending on the temperature of the hot gases washing it and the temperature of the water at its inlet and outlet, which largely depend on the type of fuel and the mode of the furnace. To find out the total power, it is necessary to multiply the useful area of \u200b\u200bthe heat exchanger by the specific power:

Qy \u003d k (T m -t m), kcal/hour, where:

K\u003d 12 kcal / hour per 1 ° C - heat transfer coefficient from the heating medium to the coolant through the steel surface;

T m- average temperature of the heating medium (max.+min./2), o C;

tm- average coolant temperature in the register (inlet + outlet / 2), o C.

If the furnace will work constantly, for example, on coal, then:

Tm=1000+600/2=800 o C.

tm=80+60/2=70 o C.

Qy \u003d 12 (800-70) \u003d 8760 kcal / hour or 10.2 kW.

If the stove is wood-burning and will work periodically (about 2 hours), then the temperature of the hot medium will be lower (maximum: 700 and 300, respectively) and at the same coolant temperature we get:

Qy \u003d 12 (500-70) \u003d 5160 kcal / h or 6 kW - the maximum that can be obtained from 1 m 2 of its surface.

The register area is calculated depending on its type. If it is made of sheet metal, then the total area that is in contact with the hot medium is calculated. In the case of using a round pipe heat exchanger, their diameter (in m) is multiplied by 3.14 and the total length of the pipes in contact with hot gases. If the pipes are rectangular, the perimeter of their section is taken and also multiplied by their length. If the boiler is combined, consists of different pipes and sheet metal, then their area is calculated separately, and then summed up.
If the total required power of the heat exchanger, the type of fuel and the mode of combustion (and hence the specific power) are known, then it is easy to determine the required useful area of \u200b\u200bthe future boiler and its dimensions, depending on what materials it will be made of (pipes or sheet steel):

S=Q total /Q y, m 2 .

A heat exchanger for a furnace or boiler can also be made with your own hands from sections of cast-iron radiators, even used ones. If sections of an old radiator are used for this, then before assembly they must be washed from the inside with a weak solution of hydrochloric acid (6-7%), and then with clean warm water to clean them inner surface from all deposits. In addition, it is necessary to disassemble the radiator into sections (even a new one) using a special key and replace the rubber or cardboard gaskets between them with asbestos threads impregnated with graphite grease. After that, having calculated the required number of sections for the heat exchanger (the area of each is about 0.25 m2), they are connected into one structure.

Such a register may consist of one or two rows of sections. The connection of the pipes of the heating system to such a design is carried out using threaded connections and appropriate adapters, corners and spurs, as well as when installing cast-iron radiators, but to seal the threaded connections that will be under the influence high temperature, it is also necessary to use asbestos threads, and not tow, as usual.

After the manufacture of such a heat exchanger, even before installation in the furnace, it is necessary to check its tightness, and for this it is necessary to pour water into it and make sure that there are no leaks. Such a heat exchanger will have rather large dimensions, so it is better to install it not in the firebox, but in the chimney or stove hood. Moreover, cast iron does not tolerate sudden temperature fluctuations, and when exposed to flame on one side and cold water on the other, it can crack.

Heat exchangers, coils - for most of us, these terms are incomprehensible. Another thing is radiators, dryers and batteries, because we encounter them every day. By the way, these are also heat exchangers, more precisely, some of the types.

This article will discuss how to make a heat exchanger yourself.

Features of heat exchangers

The creation of a heat exchanger is hardly possible without a preliminary study of the features and principle of operation of this device. In general, a heat exchanger is a device for exchanging thermal energy between two environments that do not have their own energy source. A stove, for example, is not a heat exchanger, while a bench that passes smoke gas through itself and heats the air in the room with it is one.

Another, more primitive type of heat exchanger can be considered the process of cooling a bottle under the pressure of cold tap water. In this case, the water is heated, and the liquid inside the bottle is cooled.

What determines the efficiency of a heat exchanger

First of all, the efficiency of this device is affected by the difference in temperature between the two media - the larger it is, the more energy they exchange.
Another equally important factor is the thermal conductivity of the material.
Finally, the heat exchange area is directly proportional to the efficiency of the device.

Important! Any pipeline through which a liquid circulates at a temperature different from the air temperature is considered a heat exchanger.

What are heat exchangers made of?

There are a great many designs of this device today. Each craftsman who was engaged in the manufacture of a heat exchanger tried to bring something of his own, somehow improve it. Therefore, it is impossible to consider all options. Meanwhile, most popular accessories are given below:

collectors;
car radiators;
registers;
heating radiators;
metal containers;
coils.

Manufacturing technology

The simplest device of this type can be considered copper pipe several meters long, rolled up in rings and installed in a barrel of water in such a way that only the entrance and exit remain outside. Such a design (called a “coil”) is capable of cooling or heating the liquid in the barrel, depending on what exactly is needed (heating is required in most cases).

The “serpentine” cuts into the pipeline next to the furnace or into the storage tank. The spiral pipe is installed at a height of 1.5-2 m and becomes additional source heat.

Important! If the stove is used not only for heating, but also for hot water supply, then the heat exchanger should not take more than a tenth of the heat generated by it.

Separately, it is worth talking about how long the pipe will be, for example, 2 kilowatts. The main criterion in this case is the thermal conductivity of the material. Let's say the pipe diameter is 2 cm, and the temperature difference is 40ᵒС. If you make simple calculations, it turns out that:

metal-plastic pipes with their thermal conductivity coefficient of 0.3 will require more than 4 km;
steel pipes with an indicator of 50 - 25 m;
copper pipes with thermal conductivity over 380 - only 3 m.

After such arithmetic problems, it is quite obvious that the most suitable material is copper. Moreover, this metal is easily bent and connected with a threaded fitting.

The most suitable option for a boiler or furnace. For its manufacture, you will need a metal tank of twenty liters and two copper tubes.

Step one. If there is no suitable tank, then sheet steel 2.5 mm thick is taken and a tank of the required volume is welded from it. Welding must be carried out with a minimum thickness of seams.

Step two. The tank is installed at a height of 1 m from the floor, but no further than 3 m from heating furnace. Two holes are made in it: one on the right, near the bottom of the structure, the second on the left, at the highest point.

Step three. The lower outlet is brought to the furnace with a minimum downward slope of 2ᵒ. At the same time, the upper outlet is connected with a slope of 20ᵒ, but in the other direction.

Step four. At the outlet of the lower outlet, a drain valve of the storage tank cuts into. At the lower point of the same outlet, another tap cuts in - to drain the entire system.

Step five. Upon completion of installation, the heat exchanger is checked for leaks. For testing purposes, it is filled with water under slight pressure - this will detect leaks, if any.

tube board

A heat exchanger with such an intricate name can also be made by hand, although this will require an experienced welder or skills in working with a welding machine.

For manufacturing you will need:

sealed metal tanks, 2 pcs.;
copper tubes of small diameter, 15-20 pcs.

The tanks are located at the edges and are interconnected by copper tubes installed at an angle at different points of the tanks. Water will move from one reservoir to another, and between them, in the place where the connecting pipes pass, and heat will be exchanged.

Important! This scheme formed the basis for heating multi-storey buildings.

Water jacket

An equally popular type of heat exchanger is the so-called water jacket. It consists of two sealed tanks of different diameters, with one of them placed in the other. But we note right away that such a design is quite difficult to manufacture, and it is impossible to cope with it on your own without special skills.

What else can be used

If for one reason or another it didn’t work out to find a pipe made of copper, then you can try to find something suitable in the “home” scrap metal dump (every owner should have it). For example, a coil can be replaced with an old heated towel rail, or cast-iron batteries can also be used, after checking them for leaks.

Ready-made heat exchangers can also be considered radiators from automobile stoves. They can be used as heating elements by thinking through adapters and, if necessary, by connecting several radiators to increase the total heat exchange area.

Great fit and old geysers for heating water. Moreover, in this case, you don’t even have to redo anything.

Operation features

There are a number of requirements that must be followed during the operation of this device so that it lasts as long as possible without causing absolutely no harm.

It is undesirable to fix the heat exchanger pipes (if any) on the walls of the room with fixed fasteners due to the high temperature and, as a result, the expansion of the metal.
If it is necessary to seal the connection of the pipeline with the heat exchanger, then only a material that can withstand high temperatures can be used for this.
Do not pour water into an already heated brick oven with a heat exchanger.
If the productivity of the furnace is low, then it is undesirable to install an overall heat exchanger on it, since it will take too much energy from it.

This option is suitable for those who plan to heat several rooms, but at the same time love live fire.

Design

The main element of such a system is a fireplace stove, from which numerous pipes filled with a coolant (often water) go in all directions.

The liquid can circulate both naturally and forcibly - with the help of special pumps. In other words, the furnace heats the coolant, and the pumps carry it over the entire heated area.

Installing a heat exchanger allows you to significantly increase the efficiency of the heat generator, and instead of one room, as in the previous versions, you can heat two at once without any special costs.

Main types

The modern market offers a wide variety of fireplace stoves, and all of them can be equipped with a heat exchanger if necessary to heat a large area. At the same time, someone pays attention to the type of fuel used, someone to power. Below are the most popular options.

The device on pellets, as the name suggests, is different in that instead of wood it is filled with pellets - environmentally friendly fuel, which is produced by pressing waste from the woodworking industry and is supplied in the form of granules.

The main reason for the popularity of this type of fuel is its low cost. Moreover, when burning, it practically does not emit soot, so it is commonly believed that the future is behind it.

Cooking ovens are no less popular, and the reason for this is their multifunctionality. With their help, you can not only heat the room, but also cook food. Original, practical and probably even romantic (meaning cooking over a fireplace).

conclusions

Now, after reading the article, you should understand what a furnace heat exchanger is and what its purpose is, as well as how to make its simplest options yourself. This is not as difficult to do as it seems at first glance, you just need to decide on the type of heat exchanger and choose best option heating system.